Quoting Allison Ricker:" I am 33 weeks pregnant and after I had an orgasm my stomach got very crampy and hard as a rock( probably ... [snip!] ... the uturus is contracting) but after my SO and I were done having sex I felt nauseous. Has anyone elte experienced this?"it could be.. if you were laying on your back... plus if you combine that with rapid heart rate. that can do it.